Help with Duplifaces
I would also like to know how to solve this correctly.

As far as I know it is a limitation of the current system and there is no way around it at the moment like shown here and here

From my experiments moving the original to another layer or hiding it also hides their duplicates.


One workaround is making duplicates real, but that slows things down as you already mentioned.
Another workaround as mentioned in the Blender manual is moving the duplicator object's center away to some place it doesn't bother you, and move the duplicate original along with it to the same position. It wont really hide it but you can move it out of view.
The way I generally do this is by using a particle system instead, make it emit from faces with the Unborn and Died option enabled in the Render panel, and manually match the particle count to the object's number of faces. This way you can hide the original particle, move to another layer or even put in anther scene without ill effects.


Maybe someone here has a better workaround than this, and I sure would love to hear it.